Means for supplying fuel to furnaces



Oct. '28 1924. 1,513,417

' I T. A. P-EEBLES 1 I MEANS FOR SUPPLYING FUEL,TO FURNACES Filed Nov. 19. 1921 Patented Oct. 28, 1924.

UNITED STATES rnomas A. PEEBLES, orrrrrsnuaen, PENNSYLVANIA;

means roe surrnyme FUEL TO FURNACES.

Application liled November 19, 1921. Serial No. 516,381.

To all whom it may concern: a

Be it known that I, THOMAS A. Pnnsnns, residing at Pittsburgh, in the county of Allegheny and State of Pennsylvania, a citizen of the United States, have invented or discovered certain new and useful Improvements in Means for Supplying Fuel to Furnaces, of which improvements the following is specification,

A boiler plant should be designed to meet not only an average steam demand, but also to supply sufficient steam for peak loads, which are frequently two or three hundred per cent of the average load. In some cases these divergent requirements are met by building the plant sufiiciently large to meet the maximum demand. But this plan isnot desirable as what might be termed the emergenc'y portion of the plant would be idle or non-productive for a large percentage of time.

In some cases, the difficulty has been met by installing stoking mechanism having a capacity considerably in excessof that required for normal operations, and then operating the boilers as high as 400% during peak periods. Such excessively large stoking mechanisms cannot however be operated economically when only an average demand is to be satisfied.

Experience has shown that when the coal fed to a stoker consists of large and small lumps, the operation of the stoking mechanism and the combustion of the coal on the rate bars are more or less, irregular. Hence 1t has become the general practice to crush the coal to lumps substantially uniform in size. In this crushing operation, a very considerable percentage of the coal is pulverized or reduced to such small particle's that when mingled with the lumps, it will render the mass comparatively dense, so that the air for combustion will not readily permeets a charge on the grate bars. And further, the pulverized or comminuted material will be immediately consumed on entering slowly, and hence thegeneration of heat is irre lar.

T e object of the invention described herein is to eifect a segregation of coal dust or pulverized coal from the larger lumps or pieces to utilize the coarser pieces in the normal operation of a boiler and to utilize the pulverized coal or coal dust to supplement the generation due to' the combustion of the the furnace while the lumps will burn more coarser coal, at times '"when the demand for steam is in eXcess'of-normal.

tion is hereinafter more fully described and claimed.

The accompanying, drawing formin a part of this specification, illustrates iagrammatically apparatus adapted to the practice of the invention disclosed herein.

In the practice of the invention the coal is fed in any suitable mannerto a crushing mechanism l of any suitable construction from which the coal is transferred to a suitable stoking mechanism, whereby the coal is fed onto the fuelsupporting member in the furnace of avapor enerator. During the movement of the coa "from the crushing mechanism to the stoking mechanism, dust or particles of coal of a size or weight below a predetermined maximum are removed from the coal, so that coal fed by the stoker is practically free from finelycomminuted coal, which is stored for use in the furnace when the age rating.

A convenient apparatus for carrying out the steps outlined consists of a crushing mechanism 1, from which the coal passes through a chute 2 to a conveying mechanism 3 whereby the crushed coal is delivered to a storage bin 4. From this bin the coal is delivered by a spout 5, as required, to the hopper 6 of the stoking mechanism 7. The

The invenv operation of this stoking mechanism is regulated to,supply coal at a rate suitable to maintain a pressure of vapor in thegeneration'required for normal operations.

In order to remove from the coal after passing through the crusher, all dust or particles below a predetermined minimum size, the chute 2 is profided with oppositely disposed ports or openings 9, adapted to be connected to suitable means whereby a current of air is caused to flow through the stream of coal passing down the chute and to carry with it coal dust or fine particles of coal. In the construction shown, one of the orts is connected to an exhaust fan 10 w ich has its outlet connected to a storage bin 11, in which the dust and fine particles of coal are segregated from the air.

This storage bin is provided at its lower end with a feeding mechanism 12 of any known construction preferably operated by air in addition to that entering With't-he fuel, is required. may be admitted through a port or ports in the Wall of the furnace.

In tbeoperation of a boiler plant embodying the improvement described herein, fuel for operating at normal rating will be supplied by the stokers. On an increase of load, the attendant-Will start the motor of the feed mechanism 12 and open the valve controlling the How of steam to the injector nozzle 15. As the feeding mechanism 12 is adjusted to so supplement the s'toker feed, that the boiler may be operated up to the maximum rating, the amount of fuel fed may at times exceed the requirement. In such case, the stoking mechanism Will be automatically adjusted to feed less coal.

It is characteristic of the improvement claimed herein that in the practice of the invention, coal, free from dust, is fed by the stoker and that by utilizing the pulverized coal and dust to operate the boiler above normal rating, the employment/of excessively large stoking mechanism is avoided, and the employment of a plant larger than necessary to supply steam for average loads is rendered unnecessary.

it should be understood that the element 1 is merely a crushing device for red large lumps to a size in Which they c conveniently fed to a furnace 'by st mechanism.

I claim herein as my invention:

1.111 a steam generating plant, the com-- bination of means for crushing coal to 117.11 of approximately -uniform size, means removing the pulverized or fine particles from the lumps of the crushed mass, a furnace, a stoking mechanism for feeding the cleaned lumps to the furnace, means for conveying cleaned-lumps from the crushing means to the stoker, and means independent of the stoking mechanism for feeding the dust of pulverized particles removed from the crusli ed ma'ss to s'aidfurnace.

2. In a steam generating plant, the combination of means for crushing coal to lumps of approximately uniform size, a storage bin, means for removing the dust or fine particles from the crushed mass to the place of storage, a furnace, a stoking mechanism for said furnace, means for carrying the lumps from the crushing and segregating means to the st-oker and means for conveying the fine particles of pulverized material from the bin to said furnace.

3. in a plant for generating steam, the combination of means for segregating pulverized coal or dust from lumps, a storage biufor the reception of coal dust, a furnace, a stoker for said furnace, means for conducting the lumps free of dust frontthe crushing and segregating means to the stoker and means for feeding the coal dust from the storage bin to the said furnace.

In testimony whereof, I have hereunto set my hand.

THONLAS A. PEEBLES. 

